Fan construction



May 14, 1963 w. SPEAKER FAN CONSTRUCTION Filed June 8, 1961 F'IGQI TOR.

AKER

NE g m W W m/. N E R M L H\S ATTORNEY United States Patent 3,0,314 FAN CUNSTRUCTIUN Lawrence W. Speaker, Louisville, Ky, assignor to General Electric Company, a corporation of New York Filed June 8, 1961, Ser. No. 115,673 2 Claims. ((Jl. 62279) The present invention relates to fan construction and more particularly to an arrangement for damping the zolliand vibrations of metallic fan blades secured to a fan It is well known that a fan having thin metallic fan blades produces a great deal of noise due to vibrations set up in the fan blades during rotation thereof. This is especially true when the fan is used in an environment wherein small objects carried in the air stream are likely to impinge against the fan blades. For example, it is sometimes desirable in air conditioning apparatus to direct condensate water onto the fan blades of the condenser fan in order to atomize this water and cause it to. be carried in the air stream flowing through the condenser. These water droplets upon hitting the thin metallic fan blades produces a great deal of vibration in the fan blades and the resultant noise is objectionable. This is especially true, when this arrangement is used in an air conditioner of the room air conditioner or windowmounted type, in which the noise of the water droplets hitting the fan can be distinctly heard from within the room being conditioned.

It is therefore an object of the present invention to provide an improved fan construction adapted to damp the vibrations of thin metallic fan blades attached to a rotatable fan hub.

Another object of the present invention is to provide an improved fan construction especially adapted for use in combination with air conditioning apparatus in which condensate water droplets are atomized by the fan blades and designed to damp the noise vibrations caused by impingement of water droplets against the fan blades.

Further objects and advantages of the invention will become apparent as the following description proceeds, and the features of novelty which characterize the invention will be pointed outwith particularity in the claims annexed to and forming a part of this specification.

In carrying out the present invention, there is provided a fan including a hub having an annular fan blade support section provided with a plurality of spaced apart grooves. In the bottom of each of the grooves there is formed a slot extending through the annular support section of the hub. A plurality of metallic fan blades are provided each having a base portion which fits into one of the grooves of the annular section and having tab members adapted to extend through the slots in the grooves. The tabs are transversely bent on opposite sides of the annular section to secure the blades against centrifugal force during rotation of the fan.

A resilient polymeric material is disposed in the slots of the hub member and surrounding the base portion of the fan blades thereby providing a resilient damping material between the fan blades and the hub for deadening sound vibrations of the fan blades during rotation thereof.

For a better understanding of the invention reference may be had to the accompanying drawings in which:

FIG. 1 illustrates an elevation view, partially in section, of the fan of the present invention;

FIG. 2 is a front view of the fan hub showing spacedapart grooves disposed around the annular fan blade support section of the hub;

FIG. 3 is an enlarged cross sectional view of a portion of the annular support section of the hub showing the base of the fan blade extending into the groove of 3,689,314 Patented May 14, 1963 ICC the hub with the tab thereof extending through the slot in the base of the groove; and

FIG. 4 illustrates an air conditioner, partially in crosssection, utilizing the fan of the present invention for atomizing Water droplets directed onto the fan blades.

Referring now to FIG. 1, there is shown a fan including a hub generally designated by the reference numeral 2. In order to connect the hub to a rotatable shaft, there is provided a sleeve 3 adapted to be pressed onto the shaft or to be firmly attached to the shaft in any other manner well known in the art. Extending outwardly from the sleeve 3 of the hub is an annular support section or frusto-conical flange section 4 to which are attached a plurality of fan blades 6. Referring to FIG. 2, it can be seen that the annular support section 4 of the hub 2 is provided with a plurality of grooves 7 which may be either machined into the annular flange 4 or may 'be formed therein by stamping or other suitable means. It should be noted that the grooves 7 in the hub need not be radially extending, as illustrated in FIG. 2, but may be arranged on a slant or angle with respect to the axis of the hub. The grooves, may even be of irregular form, such as curved or serpentine in shape. It is, however, desirable that they be equally spaced around the support section 4 to provide equidistant mounting for the fan blades. In the base or bottom of each of the grooves 7 there is provided at least one, and preferably more than one, slot 8 extending entirely through the support section 4 of the hub.

Each of the fan blades 6, which may be of any suitable configuration, is provided with a base section 9 adapted to fit within the grooves :8 of the annular support section in the hub. As may be seen in FIG. 3, the base section 9 of the fan blade 6 extends into the groove 7 of the annular flange section 4. The tab members 11 are inserted into the slots 8 of the grooves and transversely bent with respect to the slot thereby preventing radial movement of the fan blades 6 away from the flange section 4 during rotation of the fan.

It will be noted in FIG. 3, that the grooves 7 are substantially wider than the thickness of the metallic fan blades. Thus, the base section 9 fits within the grooves 7 of the fan blades with room to spare on opposite sides of the base section. In the space in the grooves 7 on opposite sides of the base section 9 is inserted a resilient polymeric between the sides of the base section 9 of the fan blades and the sides of the grooves 7 of the annular flange 4.

This polymeric material may be a plasticized vinyl or rubber like material, such as plasticized polyvinyl chloride or a plasticized epoxy resin, which adheres to the base. section 9 of the fan blades and supports the fan blade within the grooves 7 of the annular flange 4. The polymeric material, upon curing, cooperates with the sides of the grooves 7 to firmly support the fan blades 6 outwardly in spaced relation around the hub. Actually the bent tab 11, as will be noted in FIG. 3, only serves as a precautionary measure to prevent the blade 6 from being thrown away from the hub in case the polymeric material for some reason fails to hold the blade.

By retaining the fan blades 6, or the base portion 9 of the fan blades in the resilient polymeric material, the vibrations of the fan blades are effectively damped and the noise of these blades is effectively deadened during rotation of the fan. Thus, anything hitting the fan blades causes a dull thuddiug sound that is immediately damped, instead of setting up a resonant vibration which may be transmitted by the fan blade which acts as a sounding board.

In assembling fans of this general construction, it has been found desirable to insert the resilient polymeric spacers material into the grooves 7 prior to placing the base 9 of the fan blades therein. The polymeric material then uniformly adheres to the base 9 as it is inserted into the groove. The fan blades are usually held in place by a suitable fixture while the entire fan is placed in a suitable oven in order to cure the resilient polymeric material. After the polymeric material is cured the blade supporting fixture is removed and the tabs 11 are turned or bent over with respect to the annular support section 4.

Referring now to FIG. 4 there is shown what is believed to be one of the most important applications of a fan of this type. In FIG. 4, there is illustrated an air conditioning unit 16 including an outer case 17 divided into an indoor section 18 and an outdoor section 19 by a barrier 21. Arranged within the unit is a refrigeration system including an indoor or cooling unit 22 and an outdoor or condensing unit 23. Also positioned in the outer compartment '19 is a compressor (not shown) which compresses a refrigerant gas and pumps it through the refrigeration system. Provided within the case is a fan arrangement adapted to move separate streams of air from the enclosure to be conditioned and from the outside through the respective compartments of the unit. More specifically there is provided a fan 24 in the indoor or inner compartment 18 and a fan 2 having the construction of the present invention in the outer compartment 19 of the unit. In the illustrated embodiment of the invention these fans are driven by a motor 27 mounted within the barrier 21 of the unit.

It is well known that water condenses out of the air stream being circulated over the cooling unit 22 of an air conditioner of this type. This water is collected in a drip tray 28 and carried by an insulated conduit 29 into a condensate disposal sump 31 which, in the illustrated embodiment of the invention, is formed in the base of the outer compartment 19. In the illustrated embodiment of the invention, the outer compartment 19 is divided by a fan orifice partition 32 into high pressure and low pressure sides, respectively designated 19a and 1%. That is, the side 19a upstream from the fan 26 is of a relatively high pressure whereas the side 19b on the downstream side of the partition 32 is of relatively low pressure.

Means are provided in the unit for directing water droplets against the fan blades 6 of the fan in the outer compartment. $111 the illustrated embodiment of the invention this means includes an opening 33 in the bottom of the partition 32 through which air can flow from the high pressure side 19:; of the partition 32 to the low pressure side 1% of the partition 32. Air fiowing through the opening 33 creates a violent agitation of the water collected in the condensate sump 31 and causes water droplets to be carried out of the water into the air stream entering the fan 26. As these water droplets hit the fan 26 they are atomized by the fan and sprayed from the tips of the fan blades into the remaining portions of the outer compartment 1% and, thereby carried by the air stream flowing through the outer cornpartment onto the condensing unit 23. Extending upwardly from the base pan is a vertical baffie 34 against which the air stream flowing through the opening 33 impinges upon thereby further enhancing the agitation of the water in the sump and aiding the entrainment of water droplets into the air stream entering the fan 26. Obviously other means can be employed for directing condensate water onto the fan blades, such as a pump in the condensate sump 31 or a slinger attached to the fan itself and dipping into the sump.

It will be noted that the fan 2 is of the type previously described, and contains fan blades 6 attached to the support section 4 of the hub by means of a resilient polymeric material so that sound caused by water impingement against the fan blades is elfectively clamped by the resilient connection at the base of the fan blades. The water droplets impinging agamst the fan blades 6, instead of creating a loud ringing sound, create a dull thud which has been found to be much less objectionable than the high ringing pitch caused by undamped fan blades. It has been found that a fan of this construction, when used in combination with a condensate disposal means of this type, greatly reduces the overall noise output of the air conditioning unit and makes practical the use of condensate disposal arrangements of this type in windowmounted or wall mounted room air conditioners.

While in accordance with the patent statutes there has been described what at present is considered to be the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention and it is, therefore, the aim of the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a room air conditioner, the combination comprising a refrigeration system including a cooling unit adapted to condense water out of an air stream, means for collecting said water from said cooling unit, a water disposal means in said unit including a fan and means for directing droplets of water from said water collecting means into said fan thereby to atomize said Water droplets during rotation of said fan, said fan including a hub adapted for connection to a rotatable shaft, said hub having an annular section provided with a plurality of spaced apart grooves, said grooves having at least one slot in the bottom thereof extending through said annular section, a plurality of fan blades each having a base portion adapted to fit within a groove of said hub, tab members extending from said base portion of said fan blades and adapted to extend through said slots in said bottom of said grooves, said tabs being transversely bent on the opposite sides of said hub to retain said blades against centrifugal force during rotation of said fan, and a resilient polymeric adhesive material in said grooves and surrounding said base section of said fan blades for deadening sound vibrations in said fan blades caused by water droplets impinging against said fan blades.

2. In a room air conditioner, the combination comprising a refrigeration system including :a cooling unit adapted to condense water out of an air stream, means for collecting said water from said cooling unit, a water disposal means in said unit including a fan and means for directing water droplets from said water collecting means onto said fan thereby to atomize said water droplets during rotation of said fan, said fan including a hub adapted for connection to a rotatable shaft, said hub having a fan blade support section provided with a plurality of spaced apart radially extending grooves, said grooves having slots in the bottom thereof extending through said support section, a plurality of fan blades each having a base portion adapted to fit within said radial grooves of said hub, said base portion of said fan blades being of a narrower width than the width of said grooves to provide space on opposite sides of said base portion, tab members extending from said base portions of each of said fan blades and adapted to extend through said slots in said bottom of said grooves, said tabs being transversely bent on opposite sides of said support section to retain said blades against centrifugal force during rotation of said fan, and a resilient polymeric adhesive material in said space on opposite sides of said base section of said fan blades for cooperating with the sides of said grooves to support said fan blades outwardly from said support section, said resilient polymeric adhesive material also damping sound vibrations of said fan blades caused by Water droplets impinging against said fan blades.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Bouvy Mar. 7, 1939 Gruiteh Apr. 7, 194-2 Dean May 6, 1952 Redding June 30, 1953 Zeidler Oct. 26, 954 Howell May 10, 1960 6 FOREIGN PATENTS Great Britain Mar. 5, 1898 Great Britain Aug. 3, 1910 France Apr. 9, 1918 Germany Dec. 29, 1939 Germany Nov. 3, 1951 

1. IN A ROOM AIR CONDITIONER, THE COMBINATION COMPRISING A REFRIGERATION SYSTEM INCLUDING A COOLING UNIT ADAPTED TO CONDENSE WATER OUT OF AN AIR STREAM, MEANS FOR COLLECTING SAID WATER FROM SAID COOLING UNIT, A WATER DISPOSAL MEANS IN SAID UNIT INCLUDING A FAN AND MEANS FOR DIRECTING DROPLETS OF WATER FROM SAID WATER COLLECTING MEANS INTO SAID FAN THEREBY TO ATOMIZE SAID WATER DROPLETS DURING ROTATION OF SAID FAN, SAID FAN INCLUDING A HUB ADAPTED FOR CONNECTION TO A ROTATABLE SHAFT, SAID HUB HAVING AN ANNULAR SECTION PROVIDED WITH A PLURALITY OF SPACED APART GROOVES, SAID GROOVES HAVING AT LEAST ONE SLOT IN THE BOTTOM THEREOF EXTENDING THROUGH SAID ANNULAR SECTION, A PLURALITY OF FAN BLADES EACH HAVING A BASE PORTION ADAPTED TO FIT WITHIN A GROOVE OF SAID HUB, TAB MEMBERS EXTENDING FROM SAID BASE PORTION OF SAID FAN BLADES AND ADAPTED TO EXTEND THROUGH SAID SLOTS IN SAID BOTTOM OF SAID GROOVES, SAID TABS BEING TRANSVESELY BENT ON THE OPPOSITE SIDES OF SAID HUB TO RETAIN SAID BLADES AGAINST CENTRIFUGAL FORCE DURING ROTATION OF SAID FAN, AND A RESILIENT POLYMERIC ADHESIVE MATERIAL IN SAID GROOVES AND SURROUNDING SAID BASE SECTION OF SAID FAN BLADES FOR DEADENING SOUND VIBRATIONS IN SAID FAN BLADES CAUSED BY WATER DROPLETS IMPINGING AGAINST SAID FAN BLADES. 